The invention relates to a data transmission method between a network part of a General Packet Radio Service and a subscriber terminal comprising: an RLC/MAC (Radio Link Control/Medium Access Control) protocol layer and an LLC (Logical Link Control) protocol layer employing the services of the RLC/MAC protocol layer as data link layers; in data transmission an LLC frame of the LLC layer is placed in an RLC data block of the RLC/MAC layer.
A problem with the above arrangement is that it is not optimal. According to prior art LLC frames are not necessarily equally divided into RLC data blocks but one LLC frame may require more than one RLC data block so that the entire LLC frame can be transmitted over the radio path. An LLC frame can also be shorter than one RLC data block, therefore depending on the situation one RLC data block could hold several LLC frames. However, according to prior art two LLC frames can at the most be placed in an RLC data block. Then, if the RLC data block could in principle have held more than two LLC frames, e.g. three LLC frames, the unused capacity is lost according to prior art as it cannot be used.
It is an object of the present invention to provide a method and equipment implementing the method so as to solve the above problem. This is achieved with the type of method presented in the preamble characterized by placing more than two LLC frames in one RLC data block.
The invention further relates to a cellular network using a general packet radio service comprising: a network part and at least one subscriber terminal, data transmission between the network part and the subscriber terminal, the network part and the subscriber terminal being arranged to perform data transmission using a protocol stack where an RLC/MAC (Radio Link Control/Medium Access Control) protocol layer and an LLC (Logical Link Control) protocol layer employing the services of the RLC/MAC protocol layer act as data link layers, the network part and the subscriber terminal being arranged to use transmission units for data transmission in such a manner that an LLC frame of the LLC layer is placed in an RLC data block of the RLC/MAC layer.
The cellular network is in accordance with the invention characterized by the network part and the subscriber terminal being arranged to locate more than two LLC frames in one RLC data block.
The preferred embodiments of the invention are disclosed in the dependent claims.
The invention is based on the idea that no limit is artificially set on how many LLC frames can be placed in one RLC data block.
The method and system of the invention provide several advantages. A valuable transmission capacity of the radio path is optimally utilized, since the data transmission capacity of the RLC data blocks is fully utilized in such situations where one RLC data block holds more than two LLC frames. Thus, the data transmission rate at the radio interface increases and the use of radio resources decreases.